Process for the production of microporous sheet structures and microporous sheet

ABSTRACT

Microporous sheet structures are prepared by reacting a polymeric polyamine having a molecular weight of from about 350 to about 6000 with substantially an equivalent amount of an organic polyisocyanate in the presence of a nonsolvent for the product, shaping the reaction mixture into a sheet structure before polyaddition is complete and removing the nonsolvent.

United States Patent [72] inventors Appl. No.

Filed Patented Assignee Priority Harro Traubel;

Klaus Konig; Wolfgang Heydkamp, all of Leverkusen; Ka'rl Breer, Cologne,Flittard, all of Germany May 7, 1968 Dec. 7, 1971 Farbenlabriken BayerAktlengesellsehaft Leverlrusen, Germany May 12, 1967 Germany PROCESS FORTHE PRODUCTION OF MICROPOROUS SHEET STRUCTURES AND MICROPOROUS SHEET 13Claims, 1 Drawing Fig.

U.S.Cl ..260/2.5 AY, 117/63,117/161KP,161/159,161/160,161/164,

lnt. CL...

260/77.5 AX, 260/775 CH, 264/41, 264/331, 264/D1G. 62, 264/D1G. 77

cos; 22/00, C08g 22/36, C08g 22/4'4 [50] Field of Search 264/41, 49,DIG. 62, DIG. 77, 331; 260/775 MP, 2.5 AY, 2.5 AX,77.5 CH, 77.5AX;l17/63, 161 KP; 161/159,

[56] References Cited UNITED STATES PATENTS 1,663,652 3/1928 Gundlach252/31 1.5 3,046,172 7/1962 Reid 264/41 UX 3,190,765 6/1965 Yuan 264/41UX 3,281,396 10/1966 Barnes 264/41 UX 3,369,925 2/1968 Matsusaita et al.264/41 UX 3,388,100 6/1968 Thoma et a1 264/41 UX 3,449,153 6/1969Saligny et a1 264/41 X Primary Examiner-Philip E. AndersonArrorneys-Clelle W. Upchurch and Robert A. Gerlach ABSTRACT: Microporoussheet structures are prepared by reacting a polymeric polyamine having amolecular weight of from about 350 to about 6000 with substantially anequivalent amount of an organic polyisocyanate in the presence of anonsolvent for the product, shaping the reaction mixture into a sheetstructure before polyaddition is complete and removing the nonsolvent.

PATENIEDDEB 71911 3.625871 INVENTORS] HAPPO TPA UBEL, KLAUS KON/G,WOLFGANG HEYDKAMP, KARL BPEEP.

BY W

ATTORNEY PROCESS FOR THE PRODUCTION OF MICROPOROUS SHEET STRUCTURES ANDMICROPOROUS SHEET This invention relates to microporous sheet structuresand a method of preparation. More particularly, it relates tomicroporous sheets prepared by the polyamine-polyisocyanate-polyadditionreaction.

The production of stable aqueous dispersions of completely reactedpolyurethanes from isocyanate-containing prepolymers of high molecularweight compounds containing active hydrogen atoms and polyisocyanates,and a diamine as chain lengthening agent, in an aqueous phase, isalready known. These stable dispersions of completely reactedpolyurethanes are used, for example, in the production of nonporoussheet structures.

It is an object of this invention to provide improved microporous sheetstructures. It is another object of this invention to provide animproved method of making microporous sheet structures. It is stillanother object of this invention to provide an apparatus for conductingthe process for preparing microporous sheet structures.

The foregoing objects and others, which will become apparent from thefollowing description and the accompanying drawing showing oneembodiment of a mixing apparatus, are accomplished in accordance withthe invention, generally speaking, by providing microporous sheetstructures by reacting an organic compound having a molecular weight offrom about 350 to about 6,000 and at least two amino groups withsubstantially an equivalent amount of an organic polyisocyanate, thereaction occurring in a nonsolvent for the product, shaping the reactionmixture into a sheet structure by application to a support before thepolyaddition reaction is complete and removing the nonsolvent.

More particularly, the microporous sheet structures can be prepared byone of several mixing procedures, for example, (i) the high molecularweight prepolymer containing at least two free basic amino groups, whichprepolymer may be dissolved or dispersed in organic solvents, isdispersed in a substance which is a nonsolvent for the polyadduct to beproduced, if desired with the addition of low molecular weightpolyamines, and mixed with substantially equivalent quantities of a highmolecular weight prepolymer that has at least two NCO groups and/or alow molecular weight monomeric polyisocyanate, either of which mayoptionally be dissolved or dispersed in inert solvents, or (2) highermolecular weight prepolymers containing at least two NCO groups and/orlow molecular weight monomeric polyisocyanates, if desired dissolved ordispersed in organic solvents, are dispersed in a substance that is anonsolvent for the polyadduct to be produced, and mixed withsubstantially equivalent quantities of a high molecular weightprepolymer which has at least two free basic amino groups, whichprepolymer may, if desired, be dissolved or dispersed in organicsolvents and may already have had the nonsolvent added to it, if desiredwith the inclusion of low molecular weight polyamines, or (3) anisocyanate-containing prepolymer and/or low molecular weight monomericpolyisocyanates, if desired dissolved or dispersed in organic solvents,is mixed with substantially equivalent quantities of a high molecularweight prepolymer containing at least two free basic amino groups, whichprepolymer is optionally dissolved or dispersed in organic solvents, ifdesired with inclusion of low molecular weight polyamines, and theabove-mentioned high molecular weight prepolymer which has at least twofree basic amino groups is at the same time dispersed with a nonsolventfor the polyadduct that is to be produced. The reaction mixture preparedby any of the above three techniques is then applied on supports in sucha way that it is at the same time shaped, this application being carriedout before the polyaddition reaction is complete, and the polyadditionis completed in the sheet structure on the support, if desired atelevated temperature, preferably at a temperature below the boilingpoint of the lowest boiling solvent or nonsolvent, and the solvent andnonsolvent are removed during and/or after completion of thepolyaddition reaction.

' araliphatic Surprisingly, sheet structures obtainable by the processaccording to the invention are microporous and permeable to water vapor.The processes known to the art, in which the sheet structures areobtained from polyadducts that are free from isocyanate groups and havealready undergone complete reaction, e.g. polyurethane dispersions, incontrast, do not yield porous sheet structures.

The high molecular weight prepolymers containing at least two aminogroups to be used according to the invention (hereinafter to be known aspreadduct B) can be prepared by numerous, generally well-known methods.For example, one may use high molecular weight amino compounds, e.g. ofmolecular weight 350 to 6,000 which have two to four reactive aminogroups in the molecule. Low molecular weight polyamines may also beincluded, but in amounts of not more than 50 mols percent based on thehigh molecular weight prepolymers which have at least two amino groups.High molecular weight, amino-containing prepolymers that have proved tobe especially suitable are those compounds which are obtained byaddition of excess low molecular weight polyamines or hydrazines insolution, to compounds which carry NCO end groups (hereinafter referredto as prepolymer A) (see DAS l, l22,254, and l, 138, 220). The followingare examples of low molecular weight polyamines which may be used:ethylene diamine, diethylene triamine and polyethylene polyamines,propylene diamine-(l,3), dipropylene triamine and polypropylenepolyamines, tetramethylene diamine-( l ,4), pentamethylene diamine-(1,5), hexamethylenediamine-( l ,6), dodecamethylenediamine-(l,12) andhomologous compounds, Nrrr ansalky a laps-ltL sigh/lewd .q amimswsq h asN-methyl-l ,3-diaminopropane and N,N dimethylethylenediamine;cycloaliphatic diamines such as 1,3- and l,4-hexahydrophenylenediamine,tetrahydronaphthylene diamines, 4,4'diamino-dicyclohexylmethane,perhydrobenzidine, and 1,5-diaminodecaline; heterocyclic diamines suchas piperazine, 2,5-dimethylpiperazine and imidazolidine; aromaticdiamines such as 1,3- and l,4-phenylenediamine, l,3-, 1,4- and L5-naphthylenediamine, benzidine, 4,4'diamino-diphenylmethane, 4,4 ,4-triamino-triphenylmethane, toluylenediamines such as 2,4- and2,6-toluylene-diamine, and any mixtures of these isomers,perhydrogenated 2,4- and 2,6- toluylenediamine and any mixtures of theseisomers, as well as monoalkylated derivatives of these compounds whichare alkylated on the nucleus and/or monoalkylated on the nitrogen,diamines such as 4-aminobenzylamine, aminophenyl ethylamines,N-methyl-p-aminobenzylamine and its homologues, and l,4-xylylenediamine, hydrazine, hydrazines that are monoalkylated on one or bothN-atoms, dicarboxylic acid dihydrazides such as carbodihydrazide, adipicacid dihydrazide, aminocarboxylic acid hydrazides such as aminoaceticacid hydrazide, e-aminocaproic acid hydrazide, aminobenzoic acidhydrazide, aminosulphhydrazides such as aminobenzylsulphhydrazide andbis-semicarbazides; furthermore, one may use compounds of the formulaH,N NH-CO-ORO-CONl-l-NH, in which R denotes an alkylene radical havingtwo to l2 carbon atoms, e.g. H,N NHCOO-(CH,) -O-CONHNH,. Thebishydrazide compounds may be prepared e.g. according to US. Pat.application No. 712,355 filed Mar. l2. I968 and assigned to the assigneeof the present application. Diamines and bishydrazide compounds arepreferably used in the process according to the invention.

The reaction for the preparation of the prepolymer B which has at leasttwo amino groups, is generally carried out as follows: an NCO-containing prepolymer or low molecular weight monomeric polyisocyanatepreferably in the form of a solution is added with vigorous stirring toa solution of one of the above-mentioned low molecular weight polyamineswhich have been placed in a reaction vessel which may be cooled. Themethod of preparation of suitable NCO-containing prepolymers which areidentical with the prepolymers A and of suitable polyisocyanates isdescribed below with reference to the preparation of prepolymer A. TheNH/NCO ratio employed in this process should be greater than 1 and ispreferably between 1.5/1 and 5./l. If highly reactive polyamines areused, the NH/NCO ratio should be greater than five. The excess ofunreacted polyamine may be distilled off subsequently. If, however, onewishes to avoid a large excess of polyamines, the polyamines may, forexample, be converted into carbonates or carbamic acid derivatives.

ln addition, prepolymers B to be used according to the invention may beproducts of the type which are readily accessible by reactingprepolymers A with sulfamic acid according to DAS 1,555,907. Anothermethod of synthesizing prepolymers B is mentioned in French Pat.Specification No. l.4l5,3l7 in which prepolymers A are converted by useof formic acid into N-formyl derivatives which yield amino derivativesof the type of prepolymers B after partial saponification. Alternativelysecondary or tertiary carbinols may be added to prepolymers A inaccordance with Belgian Pat. Specification No. 675,425, and theresulting carbamic acid esters may be decomposed into the correspondingamines by a reaction catalyzed with acid catalyst.

High molecular weight, amino-containing prepolymers B of high reactivitywhich are particularly suitable for use in the process of the inventionare obtained according to DAS 1,215,375 by reacting high molecularweight hydroxyl compounds with ammonia or amines in the presence ofcatalysts, with application of pressure and heating, or in accordancewith U.S. Pat. No. 3,004,989, in which high molecular weight hydroxylcomponents are reacted with acrylonitrile and then catalyticallyhydrogenated, or according to published Dutch Application No. 66/01435by reaction of aminomethyl-5,6- dihydro-(4H) pyran derivatives with highmolecular weight hydroxyl components catalyzed with acid catalysts.Lastly, prepolymers B of good reactivity and solubility in organicsolvents may be obtained by the process described in U.S. Pat. No.2,888,439 by addition of nitroaryl isocyanates or according to FrenchPat. Specification No. 1,474,551 by addition of isocyanatobenzenederivatives to higher molecular weight hydroxyl components, followed byreduction. According to U.S. Pat. Application No. 712,355, filed Mar.12, 1968 and assigned to the assignee of the present application, highmolecular weight compounds which contain terminal OH groups can bereacted with diphenylcarbonate to undergo ester interchange with removalof phenol; carboxylic acid phenol esters react with hydrazine to splitoff phenol and form hydrazidocarbonic acid esters. These compounds mayalso be used in the process according to the invention since they carryterminal reactive NH GROUPS. All prepolymers B that can be prepared inthis way are suitable for use in the process according to the invention.

The following are examples of solvents for the prepolymers B which canalso be produced for the preparation of the latter;aromatic-hydrocarbons such as benzene, toluene and sylene; commercialsolvent mixtures such as Sangajol; cycloaliphatic hydrocarbons such ascyclohexane, methylcyclohexane, tetralin, decalin and turpentine;chlorinated hydrocarbons such as methylene chloride, chloroform, carbontetrachloride, dichloroethylene, trichloroethylene, perchloroethylene,tetrachloroethane, dichloropropane, chlorocyclohexane and chlorobenzene;esters such as methyl acetate, ethyl acetate, propyl acetate, butylacetate, formic acid esters, glycol acetate, ethylene glycolmonomethylether acetate, and ethylene glycol monoethylether acetate:ketones such as acetone, butanone-(2), pentanone-( 2), cyclohexanone,and methylcyclohexanone; esters such as di-n-propyl ether, diisopropylether, di-n-butylether, anisole, phenetole, tetrahydrofuran, dioxane andfuran; nitro compounds such as nitromethane and nitrobenzene;furthermore, one may use dimethylformamide, dimethylsulfoxide alcoholssuch as methanol, ethanol, propanol, butanol, cyclohexanol, ethyleneglycol ethers, methyl ethers, ethyl ethers, propyl ethers and in specialcases also water. Either solutions or dispersions are obtained,depending on the choice of starting compounds, concentration andpolarity of the solvents.

If solvents capable of reacting with isocyanate groups or basic aminogroups are used, the preparation and subsequent working up of theprepolymers which contain NH groups or NCO groups should be carried outbefore the solvent reacts with the compounds.

The following are examples of nonsolvents for the polyadduct which is tobe prepared from prepolymer B: aliphatic hydrocarbons such as hexane,heptane and octane; commercial solvent mixtures which may also containsome aromatic constituents, such as petroleum ether, ligroin, cleaningpetrol and mineral spirits; glycols such as ethylene glycol,propanediol-( 1,3) and 1,2), and butanediol-( 1,4); alcohols such asmethanol and ethanol, and ethers such as isopropyl ether and diisobutylether; water is used for preference.

According to the invention, the nonsolvents chosen should have avaporization number at least 1% times and preferably more than 2% timesthat of the solvent used if any. If no solvent is used, the vaporizationnumber is generally above four. Determination of the vaporization numberis described in DlN 53 170.

Prepolymer A is prepared by reacting a polyisocyanate with a highmolecular weight compound which contains active hydrogen atoms. Thefollowing are examples of suitable high molecular weight compounds whichcontain active hydrogen atoms: polyesters or polyester amides which canbe prepared by known methods from hydroxycarboxylic acids, dicarboxylicacids, polyols, polyamines, hydrazines, aminoalcohols or aminocarboxylicacids. The following are examples of acids which may be used:hydroxy-caproic acid, malonic acid, succinic acid, adipic acid,methyladipic acid, sebacic acid, thiodipropionic acid, maleic acid,phthalic acid and terephthalic acid. The following are examples ofsuitable polyols: ethylene glycol, di-, triand polyethylene glycols,polypropylene glycols, butanediol-( 1,3) and 1,4), hexanediol-( 1,6),acetals produced by the reaction of glycols with formaldehyde, glycerol,pentaerythritol, trimethylolpropane and hexanetriol-( 1,2,6). Thefollowing are examples of suitable amines: ethylene diamine,tetramethylene diamine-( 1,4), hexamethylenediamine-(1,6), piperazine,1,3- and 1,4-phenylenediamine, ethanolamino, propanolamine andN-methyldiethanolamine.

One may also use polyethers, which are obtainable for example by theaddition of alkylene oxides such as ethylene oxide or propylene oxide towater, hydrogen sulfide ammonia or polygols such as ethylene glycols,propanediol- 1,3) and (1,2), trimethylolpropane, glycerol anddi(hydroxyalkyl) alkylamines, in which case several alkylene oxides mayreact simultaneously or successively. Furthermore, polythioethersprepared e.g. by condensation of thiodiglycol with itself or by reactionwith alkylene oxides, may also be used.

Polyacetals, such as those obtained for example by the reaction ofhexanediol-( 1,6) with formaldehyde, may also be used as startingmaterials in the preparation of prepolymers A, as may also siloxanes,which are prepared e.g. from dialkylsilicone dihalides with water.

The molecular weight of the above-mentioned high molecular weightcompounds which contain active hydrogen atoms is generally from 500 to10,000.

The following are examples of suitable polyisocyanates: 1 ,4-tetramethylene diisocyanate and 1,6-hexamethylene diisocyanate,1,4-cyclohexanediisocyanate, mand p-phenylene diisocyanate, 2,4- and2,6-toluylene diisocyanate and any mixtures of these isomers as well asthe corresponding hydrogenation products, p-xylylene diisocyanate,4,4'-diphenyletherdiisocyanate, 4,4 -diphenylsulphone-diisocyanate, 4,4diphenylmethane diisocyanate, 2,2'-di-(p-isocyanato-phenyl)- propane,3,3'-dimethyldiphenylmethane-4,4'-diisocyanate,3,3-dichlorodiphenylmethane-4,4-diisocyanate, l ,5- naphthylenediisocyanate, 4,4',4"-triphenylmethane-triisocyanate,tri-p-isocyanato-phenyl thiophosphate, the reaction product of 1 mol oftrimethylpropane and 3 mols of toluylene diisocyanate-(2,4), and thereaction product of 3 mols of 1,6- hexamethylene diisocyanate and 1 molof water, having the formula OCN-(CH,),,N(CONH(CH,),NCO),. Diisocyanatesare preferred.

The high molecular weight, isocyanate-containing prepolymers usedaccording to the invention are preferably reaction products ofpolyhydroxyl compounds with monomeric polyisocyanates.

The isocyanate-containing prepolymers are prepared in known manner byheating the reactants. The NCO/OH ratio is invariably greater than onebut should as a rule not be greater than 10. A still greater excess ofpolyisocyanate may, of course, also be used, but the same result isobtained by adding monomeric polyisocyanate subsequently to theprepolymer. The prepolymers are generally of oily or waxy consistency,depending on the choice of starting components The solvents for theseprepolymers B are generally known, and as a rule not soluble e.g. inaliphatic hydrocarbons. If the NCO/OH ratio is greater than two, theprepolymers obtained are on the whole not chain lengthened whereasNCO/OH ratios less than two result in an increase in the averagemolecular weight of the prepolymers. Low molecular weight glycols suchas those mentioned above by way of example in the list of polyestercomponents may also be used in part as chain lengthening agents for thepreparation of the prepolymers in addition to the higher molecularweight starting compounds; in that case, higher molecular weightpreadducts are again obtained.

To carry out the process according to the invention, the nonsolvent isfirst added, with vigorous stirring and if desired at low temperature,to the amino-containing prepolymer which may be present in the form ofan organic solution or dispersion. The viscosity increases in thisoperation. An NCO- containing prepolymer, if desired in solution ordispersion, and/or a polyisocyanate is added to the resulting dispersionof the water-in-oil type, again with stirring. Alternatively, the highmolecular weight prepolymer containing at least two NCO groups and/orlow molecular weight monomeric polyisocyanate, optionally dissolved ordispersed in an organic solvent, may be placed in a reaction vessel andthe nonsolvent is then added with vigorous stirring. Substantiallyequivalent quantities of the high molecular weight prepolymer which hasat least two free basic amino groups, which prepolymer may be dissolvedor dispersed in organic solvents and may already have nonsolvent addedto it, is then added to and mixed with the reaction mixture, if desiredtogether with low molecular weight polyamines or hydrazines.Alternatively, the isocyanate-containing prepolymer is dissolved ordispersed in an organic solvent, and/or low molecular weight monomericpolyisocyanate, and the high molecular weight prepolymer containing atleast two free basic amino groups may be mixed together and thenonsolvent at the same time added with vigorous stirring so thatdispersion takes place. Before polyaddition is completed, the reactionmixture, which is still pourable, is applied to supports and thusshaped. Polyaddition is then completed, preferably at elevatedtemperature, preferably above 50 C. Complete removal of the mixture ofsolvent and nonsolvent is effected e.g. by evaporation, under vacuum ifrequired, or by flushing out from the resulting sheet structures.

To avoid incorporation of air bubbles in the sheet structures, whichwould impair the homogeneity of the sheet structure both as regards itsappearance and as regards its porosity and permeability to water vapor,it is advantageous to mix the components in a chamber that is free froma gaseous phase.

In order to achieve very thorough mixing of the components and, as aresult thereof, to improve the homogeneity of the resulting sheetstructures, the components that are to be mixed are advantageouslyintroduced at pressures of the order of up to 300 kg./ :m. into thechamber that is free from a gaseous phase. The choice of pressure atwhich the components are introduced depends largely on the viscosity ofthe individual components. According to the invention, the componentsare mixed at a pressure of 0.0l kg./cm. to 30 kg./cm.. The choice ofpressure at which mixing is carried out depends not only on theviscosities but also on the reactivity of the components. The mixingtime in the same way influences the homogeneity of the resulting mixtureand can be chosen to lie within a time interval of between l/5,000second and l seconds, depending on the viscosity and reactivity of thecomponents and the special nature of the mixing apparatus, taking intoaccount the pressure at which the components are introduced and thepressure at which they are mixed. According to the invention, thereaction of the components can be retarded or accelerated byapproximately adjusting the temperature of the mixing process by coolingor by supply of heat. An especially uniform sheet structure isadvantageously obtained by spraying the finished mixture on the supportthrough nozzles.

An apparatus for carrying out the process is characterized by a mixingchamber sealed ofi from the external atmosphere and having inlets forthe introduction of the reaction components and an outlet aperture. Thisarrangement insures that no air will be present in the mixing chamberduring the mixing process, which could emulsify the mixture and causethe formation of bubbles. The mixing chamber may be equipped with amechanical stirrer rotating at a speed of to 10,000 revs/min, dependingon the type of components admitted.

Mixing chambers of similar construction are already known inpolyurethane chemistry for use in the production of foam plastics, butwhen apparatus of this type is used for known purposes the presence ofair during mixing of the components does not matter. In actual fact, airis purposely introduced into the mixing chamber.

According to the invention, the inlets for the components areadvantageously provided with nozzles to insure better distribution andmixing of the components. By suitably adjusting the direction ofinjection of two or more nozzles, for example, used for injectingcertain components that are difficult to mix, an additional mixingeffect can be achieved which, particularly, serves to mix thesecompounds. In fact, a stirrer is not always necessary if the componentsare sufficiently mixed, for example by currents set up as a result oftheir being injected into the mixing chamber. Of course, the two methodsmay be combined. Open or closed direct flow or counterflow nozzlessuitable for this purpose which are already known may be used asinjection nozzles. The cross section of the outlet aperture of themixing chamber is advantageously adjustable so that the mixing pressurein the mixing chamber can thereby be regulated in the simplest manner.Valves of variable cross section of flow, for example, may be used forthis purpose, or alternatively replaceable nozzles of different crosssections of flow may be screwed into the outlet aperture. The inner wallof the mixing chamber is kept as smooth as possible to prevent theformation of deposits. Similarly, if a stirrer is employed this shouldalso be so constructed that formation of deposits is avoided. A pinstirrer has proved to be advantageous for this. The volumetric capacityrequired for the mixing chamber depends to a certain extent on thelength of stay of the components and their rate of through-put.

An apparatus for carrying out the process will now be explained with theaid of an embodiment given by way of example and described withreference to a drawing.

The mixing chamber 1 is equipped with pin stirrers 2 and surroundedexternally by a tempering device 3. The inlet pipes 4 and 5 are providedwith shut-off taps 6 and 7 and have injection nozzles 8 and 9. Theoutlet 10 is provided with a cone valve 11 of adjustable cross sectionwhich is joined to the nozzle 12.

The porosity and mechanical properties of the products of the processare largely determined not only the starting materials and the NCO/NHratio but also by the proportion of solvents and above all by the extentof polyaddition before the shaping operation.

The combination which is most suitable and the proportions of startingcompounds required to give a polyadduct with suitable properties, can bedetermined by a preliminary test in the homogeneous phase. The solutionof prepolymer containing amino groups is reacted with the appropriateisocyanate component in a solvent for the polyurethane that is to beformed, the solvent is evaporated, and the homogeneous film that hasbeen formed is tested.

In order to obtain polyaddition products with as high a molecular weightas possible, it is preferred to react approximately stoichiometricquantities of basic component and isocyanate component. in principle,the NCO/NH ratio can be styrene, polyamides and polyurethanes.Stabilizers or light protective agents may also be added.

The microporous polyadducts may, in addition, be crosslinked.Cross-linking agents may be added to the reaction mixvaried to a greatextent. Substantial deviations from the ture or to the finishedmicroporous film. stoichiometric amounts generally lead to products ofinferior Suitable cros -linking agen s are, for example, formalquality.dchydc, compounds which split off formaldehyde, and perox- The porosityf h products generally increases i h h ides. Cross-linking withpolyisocyanates is preferably carried quantity of nonsolvent; as muchnonsolvent as possible should out on the finished microporous film, whenthe film is dipped therefore be introduced into the dispersion. Sincethe viscosity 10 into the solution or dispersion of a polyisocyanate andmay be rises sharply with increasing quantities of nonsolvent, theheated to elevated temperature, if desired in the presence of dispersionmay become unstable and break, and the optimum catalysts. quantity ofnonsolvent is advantageously determined in a The polyadducts may beapplied to porous or nonporous preliminary test. supports. Examples ofporous supports are knitted fabrics,

The course of the polyaddition reaction depends on the woven fabrics,fleeces, felts and split leather. Nonporous subreactivity of thestarting components as well as on the stirring strates such as glassplates, metal bands, if desired with the time. The stirring time shouldbe sufficient to insure thorough negative of a surface impregnation, orwebs of paper or woven mixing of the dispersion of the amino containingprepolymer B fabric coated with perfluoropolyethylene, are used when itis with the isocyanate component. if the stirring time is too prodesiredto obtain porous sheet structures which are to be longed, the reactionmixture may become solid. The optimum transferred by the usual reversingprocesses to porous supstirring time is therefore determined in apreliminary test. The orts, e.g. by adhesion. By this method one maycoat supports course of the polyaddition reaction of a given system canbe such as wood, split leather, cardboard, paper and woven or followede.g. spectroscopically (determination of the NCO abunwoven textile h etSOPPtiOH) or volumetrically pping the reaction with Microporous sheetstructures with good mechanical properhydrochloric acid and acktitration th dium hy roxide ties, very good flexibility and excellentresistance to solvents solution). can be produced by the processaccording to the invention. By The polyadditioh reaction can beaccdefated y know" using the process according to the invention one caneasily catalysts Saunders, polyurethanes, produce sheet structures frompolyurethane ureas that are CHEMISTRY and 8yN York 1962 P Ih verydifiicult if not impossible to prepare by conventional addition 10 thecatalysts, the reaction temperature also processes, such as reactingisocyanate-containing prepolymers fluences the rate of polyaddition. Thereactants, prepolymer B, and polyamines i somfion or i the n and p p y Aand/01' monomeric POIYiSOCYahateI are The microporous sheet structuresobtained can be finished generally mixed at room temperature or belowthis and by methods normally used for genuine or artificial leather.polyadditibh is completed at elevated temperature- They may, forexample, advantageously be used in the producin the process according tothe invention, emulsifiers such tion fl th substitutes or as diaphragmsy alcohol Sulfohate} ethbxylated P Salts of fatty The invention will befurther illustrated by the following exaclds quatemateq amines ofParaffihs may be used' AS amples in which parts are by weight unlessotherwise rule, however, emulsifiers are not employed. ifi L Fillerssuch as precipitated silicic acid, silicon dioxide or 40 M- bentoniteshould, if employed, as far as possible added to the preparation fi t ii prepolymers prepolymer B or to its solution prior to dispersion orstirred up p m A) in the mixture of solvent and nonsolvent and added inthis form to the dispersion. The quantity of filler should generally A lnot exceed 50 percent by weight, preferably 25 percent by About DQ Part5of near P p py glycol ether of weight based on thepolyadduct molecularweight 2,000 are mixed with about 336 parts of [,6- Another advantage ofthe process is that both water-soluble hexamethylehe' dhsocyahate andheated to about dyes and dyes that are only soluble in organic solventcan be the free isocyanate group content has dropped to P"- included forcoloring the products of the process. The dye is cent y Weight whichrequires about 8 to 9 hours- A l3ale y dissolved either in the organicphase or in water, depending on low oil of Viscosity 2125 lip/25 is itssolubility; it is preferably added before the preparation of A 2 thedispersion. Pigments may, for example, be stirred up in the About 250Parts of 4i4'diphehylmetham dhsbcyahate are organic phase; when thenonsolvent is dispersed in the reacadded to about 1,000 l" ofa hearPolypropylene glycol of ion mixture the pigments become distributed ithe di molecular weight 1,000, and the reaction mixture is heated tosion The pigments may f course, also b dd d to h about 80 C. for about 6hours. A viscous yellow oil is obganic phase or di i in h f f an aqueoussuspen. tained which contains 3.3 percent by weight of free isocyanatesion, if desired in the presence of thickening agents such as S P Icarboxymethylcellulose. The said dyes may also be used to A 3 color thefinished products of the process. About 1,700 parts of polyester ofadipic acid and a mixture Other high molecular weight compounds may alsobe added 0f and 2,2-dimethylpropanediol-( in the to the solution ordispersion of the prepolymer B or to the isoratio of 65135, mOlBCUlal' eg 05 number 66, are cyanate component in order to modify the polyadductswhich heated to about and about 348 Parts Of y are to be produced. Thesehigh molecular weight compounds diisocyanate are added. After about 190minutes at about 80 may be added in finely divided, solid form or insolution. C., the NCO content has dropped to 4.1 percent by weight. A

Examples of high molecular weight compounds which may pasty, pale yellowproduct is obtained, be added are such as polyvinyl chloride, polyvinylacetate, The prepolymers containing the NCO groups indicated polyvinylalcohol, polyethylene, polystyrene, below were prepared analogously to Al to A 3 from the compolyacrylonitrile, polymers of acrylonitrile,butadiene and ponents indicated Free NCO group content Higher molecularweight compound having at least two Molar (percent by Consistency or No.active hydrogen atoms Polyisocyanate ratio weight) viscosity A 4.,Linear polypropylene glycol ether molecular weight 2,000,1,6-hexamethylene diisocyanate 1:3. 5 7. 74 Colorless oil.

011 number 56. A 5 do Isometic mixture t01yu1ene-2,4- and toluyl- 1:23.8 Viscous oil.

one-2,6-diisocyanate (:20% by weight).

.. .l..'-3 Q58. ,leliqwyii- Free NCO group content Higher molecularweight compound having at least two Molar (percent by Consistency or Nti hydrogen atoms Polyisocyanate ratio weight) viscosity4,4-diphenylmethane dilsoeyanate- 1:1. 5 1. 64 Yellow resin."do..."........... 1:3 0.2 Do, pylene glycol ether molecular weight1,000, Isomeric mixture toluylene-2,4- and toluyl- 1:2 5. Do. OH number112. one-2,6-diisocya11ate (80%:20 by Weight). A 11.. Mixture of apolysiloxane of the formula HO-CI-Iz-(Si 4,4-diphenylmethanediisocyunate 1:2 3. 68 Do.

(CH3)20)12Si(CHa)2CH2OH and a linear polypropylene glycol ether,molecular weight 2,000, OH number 56, in the molar ratio 1:3. A 12..Polysiloxane according to A 11 1,6-hexamethylene diisocyanate 1:2 5. 3102 eP/25" C. A 13. Polypropylene-polyethylene glycol ether (prepared by4,4diphouylmethane diisocyanete 1:2 3.08 Yellow resin.

alternating poly-addition of 75 parts by weight of propylene oxide and25 parts by weight of ethylene oxide) molecular weight 2,150, OH number52. A 14.. Mixed polyether of 80 parts by Weight of propylene oxide1,6-hexamethylene diisocyanate 1:2 2. 1,875 cP/ C.

and 20 parts by weight of ethylene oxide, molecular weight 4,150 ,OHnumber 27.

A 15.. Polytetramethylene glycol ether molecular Weight 2,660, .....do1:2 2.68 Waxy,

H number 42. A 16.. Polytetramethylene glycol ether molecular weight1,320, .....do 2.2 Do.

OH number 85.

A 17 do 4,4-diphenylmethane diisocyanate. A 18.. Polythioether (preparedby condensation of 70 parts by .....do

weight of thiodiglycol and 80 parts by Weight of 1,6- hexanediol)molecular weight 1,570, OH number 71.5. A 19. Polyester of adipic acidand a mixture of 65 parts by weight 1,6-hexamethylene diisocyanate 1:24. 1 Salvy.

oi hexanediol-(1,6) and 35 parts by Weight of 2,2-dimethy1propanediol-(1,3),molecular weight 1,700, OH number 66. A 20. Polyesterof adipic acid and a mixture of 1,6-hexanediol and 4,4-diphenylmethanediisocyanate 1:1. 5 1. 8 Do.

2,2-dimethylpropanediol-(l,3) in the molar ratio of 11:6, molecularweight 1,870, OH number 62.

1. 46 D0. 3. 78 Yellow resin.

A 21 ..do 2,2-d1pheny1propane-4,4-diisocyanate..... 1:2 3. 42 Do. A 22..Polyester of adipic acid and diethylene glycol, molecular Isomericmixture of toluylene 2,4- and 1:2 10. 6 Highly viscous.

weight 600, OH number 187. toluylene2,6-diisocyanate (80:20 percent byweight).

Preparation of prepolymers containing amino groups about 200 parts ofprepolymer A 2 (0.163 mol NCO) in about (prepolymer B) 250 parts ofxylene are run in with vigorous stirring at about 0 B l C. A thickliquid 33.3 percent dispersion containing 0.2 mmol About 24.8 parts of4-aminophenylethylamine (0.183 mol) ofsemlrcarbazlde groups per Part lsobtamed in about 225 parts of benzene are introduced into a glass B 3beaker, and a solution of about 200 parts of prepolymer A 2 A solutionof about 200 parts of prepolymer A 1 (0.1685 (0.183 mol NCO) in about300 parts of benzene is run in with mol NCO) in about 490 parts oftoluene are run into a solution vigorous stirring (plate stirrers, 2,700revs/min). at 5 to 10 C. of about 44.5 parts of tetramethylene diamine(0.505 mol) in in the course of about 30 minutes. A milky, 30 percentsoluabout 245 parts of toluene at about 0 C. in the course of tion isobtained which contains 0.244 mmol amino groups per about 15 minutes.The thickly viscous end product contains part. 0.86 mmol ofamino groupsper part. B2 The prepolymers containing the amino groups indicated About8.5 parts hydrazine hydrate (0.163 mol) in about 176 below were preparedin a manner analogous to B 1 to B 3 from parts of xylene are placed intoa reaction vessel. A solution of the components indicated.

Content, Active N 00/ percent NH Prepolymer NH by (mmol/ No A N o.Diamine ratio Solvent weight part) B 4 A 10 Hydrezine 1:2 Benzene 0.687B5. A5 .....do 1: 0.44 B6.-... A7 ..do... 1: 50 0.825 B7..... A1....do.. 1: 50 0.465 B8..... A6 .....do... 1: 50 0.707 B9 A4 ....do---1: 50 0.87 B 10.--. A1 -....do 1; 40 0.327 B 11-.-. A 15 .....do 1: 33 30.208 B 12---. A17 .....do. 1=2 33 3 0.115 B 13---. A20 ..---do. 1:2 333 0.141 B 14-.-. A 13 0..... 1:2 33 3 0.357 B 15...- A 6Methylhydrazine., 1:2 50 0. 695 B 16...- A 2 4aminopheny1ethylam1ne..1:2 50 0.406 B 17.-.. A9 d 1:2 30 0.363 B 18.... A8 1:2Benzene.......... 40 0.155 B 19.-.- A8 1:2 Tetrahydrofuran. 40 0.155 B20.... A 15 1:2 Diiso ropylether 33. 3 0. 195 B 21-... A 16 1:2 Ethyacetate 33. 3 0.163 B 22---. A 18 1;2 Toluene 33.3 0.267 B 23.... A 81:2 Benzene... 50 0.198 B 24.... A 11 1:2 Dichloromethane 50 0. 391 B25-... A 2 5:6 Dimethylformamide 33. 3 O. 0485 B 26---. A 2 1:2 Benzene30 0. 244 B27-.-- A9 1:2 d 20 0.242 1328.... A8 1:2 50 0.185 B29. A6 1:250 0.628 B30---- A1 1:2 20 0.142 B 31.... A 15 Piperaziue 1:2 33 3 0.1 6

1 The diamine was converted into the carbonate before the reaction withprepolymer A. B 32 100 C./500 excess atmospheres H and filtered and thesol- About 9 Parts Of p ypr pyl ne g y ol-(1,2) 7O vent is evaporatedoff under reduced pressure. The yield of t r a added I about 328-5 Part8If distilled P- diamine is more than 99 percent of the theoretical, NHnitrophenyl isocyanate in about 1,500 parts by volume of number 50.5.tetrahydrofuran, and the reaction mixture is stirred for about B 33 2hours at the boiling point of the solvent. After the addition Aprepolymer is prepared from about 1,000 parts (0.5 mol) of Raney nickel,the reaction mixture is hydrogenated at about of polypropylene glycol-(1,2) ether and about 420 parts of 1,6-hexamethylene diisocyanate byheating to about 100 C. for about 2 hours, and the prepolymer is freedfrom excess diisocyanate by thin layer evaporation (135 C. bathtemperature/0.08 mm. Hg). Analysis shows an NCO-content of 3.03 percentby weight.

About 85.2 parts (1.0 mol) of about B-cyanoethylhydrazine are dissolvedin 1,500 parts by volume of tetrahydrofuran in a vessel equipped withstirrer, and about 1,380 parts (0.5 mol) of the prepolymer whichcontains NCO end groups is added in about 1,000 parts by volume oftetrahydrofuran over about 2 hours at about C. AFter stirring for about3 hours at room temperature, the solvent is removed by distillationunder a vacuum in the final stages, of up to about 2 mm. Hg. End groupanalysis shows that the pale yellow, tough viscous material produced hasa molecular weight of 2,930 (calculated 2,945) and an N content of 4.73percent by weight (calculated 4.76 percent by weight).

from a polyester of adipic acid and 1,6-hexanediol (molecular weight850) and toluylene diisocyanate (2,4-:2,6-isomer mixture 65:35 percentby weight) are heated with about 428 parts (2 mols) of diphenylcarbonate at 12 mm. Hg for about 30 minutes to about 150 C. Thetemperature is then raised to about 225 C. in the course of about 1 hourat about 100 mm. Hg. Phenol liberated during the reaction (192 parts2.04 mol) is then distilled off at about 12 mm. Hg. and a bathtemperature of about 180 C. About 100 parts (2 mol) of hydrazine hydrateare then added at about 180 C., the reaction mixture is stirred for afurther 90 minutes at about 80 C., and about 35 parts (1.95 mol of waterare distilled ofi" at 12 mm. Hg., followed by about 182 parts (1.94 mol)of phenol at 0.1 mm. Hg, bath temperature about 1 10 to about 150 C. Ayellowish wax of softening point 40C. is obtained.

PROCESS ACCORDING TO THE INVENTION Example 1 A. About 46 parts (40 mmolNH of the prepolymer prepared according to B 9 are diluted with about100 parts of benzene and stirred to form a homogenous solution. About450 parts by volume of water are added to the solution of at a rate ofabout 5 parts by volume per second by means of a stirrer apparatus(Ekato Labormix 26) to which a plate stirrer is at tached which rotatesat 4,000 revs/min., and a dispersion of water in the solution ofprepolymer B in benzene is thus prepared.

About 1,940 parts (1 mol) of an addition product prepared microporousfilm, 0.5 mm. in thickness, has a permeability to water vapor of lmg./hour/cm., a tensile strength of 40 kp/cm. an elongation at break of140 percent and a resistance to tearing of 8.4 kp/cm.

Example 2 In a manner analogous to example 1, about 22.7 parts 10 mmolNH,) of the product prepared according to B 5 are treated with about 20parts of benzene, and about 50 parts by volume of water are dispersed inthis liquid.

A dispersion of about 10 parts by volume of 0.5 molar solution of1,6-hexamethylene diisocyanate in benzene with about 50 parts by volumeof water is prepared and this dispersion of the prepolymer B5 isintroduced with stirring. After stirring for about 20 seconds thedispersion is poured on to glass plates 800 cm. in size, and the solventis evaporated at about 75 C. A microporous film is formed which has apermeability to water vapor of 4.6 mg./h./cm. and a tear resistance of 9kp/cm.

Example 3 About 38 parts (10 mmol NH,) of the prepolymer prepareaccording to B 2 are dissolved in about 30 parts of benzene. About 350parts by volume of water are dispersed in this solution at a rate ofabout 1 parts by volume per second by means of a stirrer apparatus(Ekato Labormix 26 (Ekato mixer stirrer) operating at 6,000 revs/min.About 50 parts by volume (10 mmol NCO) ofa 0.2 molar solution ofprepolymer A 14 in benzene are run into this dispersion, and afterstirring for about 15 seconds the reaction mixture is poured on to astudded metal matrix 2,000 cm.' in area. Polyaddition is completed atabout 80 C. while the solvent evaporates. A

microporous film is produced which has a permeability to water vapor of1.8 mg./h./cm.

Examples 4 to 7 are carried out in a manner analogous to example 3.

0.2 molar Quantity solution of Quantity of of water the N00 01 the Stir-Reac- Permeability Preprepolymer Quantity dispersed Preprepolymersolution of ring tion to water polymer B used NH2, of solvent (parts bypolymer (parts by preadduct time temp vapor (mgJ Ex. B used (parts) mmolSolvent added (parts) volume) A used volume) A, mmol (sec.) C. h. 0111.

4 B 7 10. 8 5 Ethyl acetate. 20 100 A 19 25 benzene" 5 15 75 1. l 5 B 218 do 40 150 A 3 40 benzene- 8 10 80 1.2 6 B 22 37.5 10 Toluene... 40 100A 3 50 benzene" 10 10 80 1 7 B 1 41 10 Benzene 50 250 A 3 25 benzene 530 80 16 Example 8 of prepolymer A prepared according to A 12 is addedto this dispersion, and after stirring for about 15 seconds, the result-About 250 parts by volume of water are dispersed in about ing product ispoured on to a silicone matrix which has a sur- 29.2 parts (20 mmol NHof prepolymer 8 prepared according to B 4 and about 30 parts of benzene.A mixture of about 10 parts by volume of 0.5 molar solution of1,6-hexamethylene diisocyanate (10 mmol NCO) and about 25 parts byvolume of 0.2 molar solution in benzene (10 mmol NCO) face area of 680cm. around the edge of which it is beaded. Polyaddition is completed atabout C. while the solvent evaporates. The resulting microporous sheetstructure has a permeabilty to water vapor of 15.2 mg./h./cm.".

Examples 9 to 16 are carried out according to example 8.

0.2 molar Water solution Quantity of incorporated prepolymerPreprepolymer Quantity by disper- Prepoly- A in benadduct B used NH2. ofsolvent sion (parts mer A zene (parts Ex. B used (parts) mmol Solventadded (parts) by volume) used by volume) 22. 7 10 Benzene 20 A 14 25 4810 ..do 100 250 A 1! 2 52 10 Dl-u-propy1ether 50 150 A 19 25 16.-." B 1782 29 Benzene., 50 250 A 3 25 .2e t$9iP meLe le szl eqiahfimethy eeqfisesyenats se smd W1 B 10 dispersion- 1 molar NCO of tho NCO f thsolution in solution of Stir- Reac- Resistance Permeability solution ofbenzene polyisocyanoto ring tion to tear to water prepolymer (parts byin benzene, time temp. propagation vapor Example A, mmol Polyisocyanatevolume) mmol (soo.) C.) (kp./cm.) (mg/l j) 5 1,6-hexamethy1enediisocyanato 2.5 5 30 75 1g 1 5 d 2.5 15 75 5 Q8 5 2.5 5 s 75 0.8 5 2. 55 60 75 5 0. 8 5 2. 5 5 s 75 3 5 2. 5 5 10 l 5 d0 2.5 5 10 54,4-diphenylmethane diisoeyanate 5 10 5 5 Example 17 Example 34 About 50parts of isopropanel are added to about 50 parts (10 mmol NH ofaprepolymer prepared according to B 13, and about 60 parts by volume ofwater are dispersed in this. About 5 parts by volume 0.2 molar1,6-hexamethylene diisocyanate solution in benzene 10 mmol NCO) areadded to this dispersion, and the dispersion is stirred for about 10seconds and poured on to glass plates 2,000 cm. in area. Aftercompletion of the polyaddition at about 80 C. and removal of the solventby evaporation, a microporous sheet structure is obtained which has atensile strength of 80 kp/cmf, an elongation at break of 400 percent, atear resistance of 2.3 kp/cm. and a permeability to water vapor of 0.9mg./h/cm. The sheet withstands being folded 200,000 times in the BallyFlexometer without damage.

Example 18 By a method similar to that used in example 17, about 20parts of benzene are added to about 22.7 parts (10 mmol NH of aprepolymer prepared according to B 5, and about 50 parts by volume ofwater are dispersed in this solution. A dispersion of about 5 parts byvolume at 0.5 molar benzenic About 50 parts of dimethylformamide andabout 20 parts of a 30 percent solution in dimethylformamide of athermoplastic, partially hydrolyzed cellulose acetate, and about 50parts of a 12 percent solution in dimethylformamide of a polyurethaneprepared from polypropylene glycol ether of molecular weight 2,000,4,4'-diphenylmethane diisocyanate and p-aminophenylethylamine (NCO/NHratio l.3) are added to about 103 parts (5 mmol N11,) of the prepolymercontaining NH groups prepared according to B 25. About 5 parts by volumeof a 0.5 molar solution of 4,4'-diphenylmethane diisocyanate in benzeneare added with vigorous stirring, and the mixture, which becomesviscous, is poured after stirring for about 15 seconds on to glassplates 2,000 cm. in area. To accelerate polyaddition, the reactionmixture is exposed to a temperature of about 80 C. for about 30 minutes,and after the plates have cooled the solvent is flushed out by immersionin water. The microporous film obtained has a permeability to watervapor of 6.1 mg./h./cm. and can withstand being bent 200,000 times inthe Bally Flexometer without damage.

1,6-hexamethylene diisocyanate solution 10 mmol NCO) in Example 35 about50 parts by volume of water is added to the dispersion prepared in thisway, and after a stirring time of about 20 About loo Parts by Volume ofmethanol are dispersed in seconds the product is poured on to glassplates 680 cm? in about 44 Parts mmOl NH2) f the prepolymer preparedacarea. After drying for about 4 hours at about 75 C. in a dryingcording to B After the i on of about 10 parts by cupboard withcirculating air, the film id detached and dried Volume of a molarSolution of lrrhexamethylene diisofor another 20 minutes. The film h ate r propagation cyanate in benzene, the reaction mixture is stirred forabout sistance of 9.3 kp/cm. and a permeability to water vapor of 4.6 15Seconds and is then poured n to a gl ss pl te of 680 cm. mg,/h,/cm inarea. After polyaddition has terminated and the solvent has Examples 19to 23 are carried out using the method been evaporated off at about 80C., a microporous structure of example 17. V is obtained which has apermeability to water vapor of 13.4

Quantity of Quantity of prepolymer (imantity water Prepoly- B used NH2 0solvent dis ersed Example mer B used (parts) mmoi Solvent added (parts)parts) B 15 29.8 20 Benzene 10 100 B 6 12.1 10 0 20 100 B 26 41 10 Ethylacetate... 20 150 B 16 24.8 10 do 40 120 B 1 41 10 150 B 19 .1 40 150 B27 41.3 10 110 B 27 41.3 10 110 B 13 71 100 B 28 54 40 250 13 5 22.7 30250 B 28 54 d0 250 B 31 50 10 Isopropanol. 50 B 30 71. 5 10 Benzene 50250 33 B 30 71.5 10 .d0 30 250 1 molar N C0 of solusolution in tion ofpoly- Stir- Reac- Permeabenzene isocyanate in ring tion bility to (partsby benzene, time temp. water vapor Example Polyisoeyanate volume) mmol(see) C.) (mg./h. cm.

1,5-naphthylene diisocyanate... l 10 20 20 110 3. 7 1,5-hexamethy1enediisocyanate. 5 10 20 0, x 4,4-diphenylmethane diisocyana 5 10 45 110 15 10 8 75 7. b 5 10 8 75 5.1 5 10 8 110 4. 7 5 10 1O 75 1. 1 5 10 1575 1. 2 1,6-hexamethylene diisocyanate... 5 10 10 75 1. 7 28 Isomeriemixture of 2, 4 and 2, fi-toluyl 6 10 10 75 1.0

(:20% by weight). 29 1,6-hexamethy1ene diisocyanate 5 10 15 75 2. 9 304,4-diphenylmethane diisocyanate... 5 10 10 60 1.0 31 5 10 10 80 1. 0 32d0 5 10 40 60 2. 9 33 4,4-diphenylmethane diisoeyanate. 5 10 10 60 2.1

mg./h.cm. and can withstand being bent 200,000 in the Bally Flexometer.

Example 36 in a manner analogous to that used in example 35, about 40parts of ethyl acetate and about 100 parts by volume of cleaning petrol(aliphatic hydrocarbon mixture of b.p. lO-140 C.) are dispersed in about62 parts (10 mmol NH of the Nib-containing prepolymer prepared accordingto B21. After the addition of a mixture of about 50 parts by volume ofcleaning petrol and about 50 parts by volume of a 0.2 molar solution inbenzene of a prepolymer A prepared according to A 19, the reactionmixture is stirred for about 10 seconds and poured on to a glass plateof 680 cm. in area, and polyaddition is completed at room temperaturewith concomitant evaporation of the solvent. A microporous film isobtained which has a permeability to water vapor of 7.1 mg./h./cm.".

Example 37 About 30 parts by volume of ethylene glycol are dispersed inabout 41 parts (14.9 mmol NH,) of a prepolymer prepared according to B17, and are added to the dispersion which is in the process of formationof about 25 parts by volume (5 mmol NCO) of a 0.2 molar solution inbenzene of the prepolymer prepared according to A 3. The reactionmixture is poured on to glass plates 680 cm. in area. The mixture isheated at about 80 C. for about 2 hours and is then cooled to roomtemperature, and the glycol is removed by washing with water. Afterdrying, a microporous sheetstructure is obtained which has apermeability to water vapor of 4.4 mg./h./cm.

Example 38 in a manner analogous to example 37, a dispersion of about 44parts (5 mmol NH ofa product prepared according to B 12 and about 100parts by volume of ethylene glycol are reacted with about 25 parts byvolume (5 mmol NCO) ofa 0.2 molar solution in benzene of-the productprepared according to A 19, and the reaction mixture is stirred forabout 10 seconds and is then poured on to metal plates 700 cm? in areaand left to stand for about 4 hours at about 20 C. After washing withwater to remove glycol and drying, a microporous sheet structure remainswhich has a permeability to water vapor of5.6 mg./h./cm.

' Example 39 About 50.5 parts 10 mmol NH ofa prepolymer preparedaccording to B 23 are mixed with about 1 part of copper phthalocyanine,about 50 parts of tetrahydrofuran. and about 50 parts of benzene andabout 40 parts of a 12 percent solution in acetone ofa cellulose acetate(containing 53.5 percent acetic acid). A dispersion is formed by theaddition of about 250 parts by volume of water. About 10 parts by volumeof0.5 molar (10 mmol NCO) solution in benzene of 4,4-diphenylmethanediisocyanate are added to the dispersion which is then stirred for about5 seconds and poured on to a glass plate 680 cm. in area, andpolyaddition heating the surrounding air to about 75 C., the solventbeing evaporated. The resulting microporous film has a permeability towater vapor of 1.4 mg./h./cm.

Examples 40 and 41 are carried out in a manner analogous to example 39.

Quantity Quantity of of water prepolymer Quantity dispersed Prepolymer BNHz. 0f Solvent (p y Solvent for the Example B used (parts) mmol Solventadded (parts) volume) Polymer used polymers d Polyvinyl chloride K-value55... Tetrahydroluran. 40 B 23 50. 5 10 Benzene 80 200 Polyvinyl acetatemolecular D0,

T t 11 dr 1 so Tti i i 1 e ra y 0 man... ermop astic, part a ly hydroTetrah droluran. B 23 10 {Benzene 50 250 lyzed cellulose acetate. y

0.5 molar Concentration solution of of the poly- Quantity of prepolymerN00 01 Stir- Heat- Permeability mers in the solvent for A in bensolutionof ring ing to water solvent; the polymer zene (parts prepolymer timetemp. vapor (mg. Example (percent) used (parts) Polyisoeyanate byvolume) A, mmol (sec.) C.) h./cm. 40 30 20 4,4-diphenylmethane 10 10 675 6. 2

diisocyanate. 3O 20 41 10 40 4,4-diphenylmethane 10 10 5 75 0. 9

diisocyanate.

alic acid IS added. After the incorporation of about 400 parts Example42 b y volume of water by dispersion, about 10 parts by volume of About37.5 parts 10 mmol NH of a prepolymer prepared according to B 22 arediluted with about 130 parts of toluene. About 3 parts of a commercialfiller of precipitated silicic acid (pH-5.5, particle size below 20;;consisting of 90 percent SiO and calcium silicate), moistened with about10 parts of toluene and treated with about 10 parts of water, are addedto the solution of prepolymer B. After about 180 parts by volume ofwater have been dispersed in this precipitate,-about 20 parts by volume(20 mmol NCO) of a l-molar solution in ethyl acetate of a prepolymeraccording to A 22 are added. The reaction mixture is stirred for about40 seconds. It is then applied to glass plates 680 cm. in area,polyaddition is completed at about C., and the solvent is evaporated.The resulting microporous film has a permeability to water vapor of5.9mg./h./cm.

Example 43 About 54 parts (10 mmol N11,) of a prepolymer preparedaccording to B 28 are diluted with about 80 parts of benzene, and amixture of about 0.4 parts of gas soot, about 1 part of paraformaldehyde(particle size 5p.) and about 0.2 parts of ox- 0.5 molar solution inbenzene of 4,4'-diphenylmethane diiso- 5 cyanate are added. The reactionmixture is then stirred for about 10 seconds and is poured on to glassplates 680 cm. in area. After completion of polyaddition and evaporationof the solvent at about 75 C., the permeability to water vapor of themicroporous sheet structure is found to be 6.6 mg./h./cm.".

Example 44 Quantity of water Viscosity (parts by volume) low iron oxidepigment, about 12.5 by volume (12.5 mmol NCO) of 0.5 molar solution of4,4-diphenylmethane diisocyanate in benzene are added, and afterstirring for about 12 seconds, the reaction mixture is poured on toglass plates- 200,000 cm. in area. After it has been heated at about 80C. until reaction is complete, a microporous sheet structure is obtainedwhich has a permeability to water vapor of 0.7 mg./h./cm

Example 45 In a manner analogous to example 44, about 80 parts ofbenzene are added to about 54 parts (l mmol NH of the prepolymerprepared according to B 28, and the viscosity is determined. Thefollowing viscosities are obtained on addition of water:

Viscosity in Ford beakers 6 mm. nozzle Quantity of water About 0.5 partsof an orange colored lead chromate pigment is added to the dispersion,about parts by volume of a 0.5 molar solution of l,5-naphthylenediisocyanate in tetrahydrofuran are added, and after stirring for about30 seconds the reaction mixture is poured on to glass plates 680 cm. inarea and heated at about 80 C. until reaction is completed, when thesolvent is evaporated. The resulting film has a permeability to watervapor of 0.7 mg./h./cm.

Example 46 About 25.6 parts (10 mmol NH of a prepolymer preparedaccording to B 24 are mixed with about 3 parts ofo-benzylhydroxydiphenyl polyglycol ether and about 25 parts of methylenechloride. After about 100 parts by volume of water have been dispersedin this mixture, about 50 parts by volume (10 mmol NCO) of a 0.2 molarsolution in benzene of the prepolymer prepared according to A 3 areadded, and after stirring for about 25 seconds, the reaction mixture ispoured on to glass plates 680 cm. in area, and polyaddition is completedat about 80 C., the solvents evaporating at the same time. A microporoussheet structure is formed which has a permeability to water vapor of 1.8mg./h./cm.

Example 47 ln a manner analogous to example 46, about 30 parts ofbenzene are added to about 11.5 parts (10 mmol NH of a prepolymerprepared according to B 3, and about 70 parts by volume of water aredispersed in this mixture. About parts of a 20 percent aqueous solutionof o-benzyl-hydroxydiphenyl polyglycol ether are added to about 50 partsby volume (l0 mmol NCO) of a 0.2 molar solution in benzene of aprepolymer prepared according to A l, and about 180 parts by volume ofwater are dispersed in this. This dispersion of prepolymer A isintroduced into the dispersion of prepolymer B, and after stirring forabout 8 seconds the reaction mixture is poured on to glass plates 680cm? in area. Polyaddition is completed at room temperature and thesolvents are evaporated. A microporous sheet structure is obtained whichhas a permeability to water vapor of l3.4 mg./h./cm.

Example 48 About 250 parts by volume of water are dispersed in aboutparts by volume of 0.5 molar solution in benzene of prepolymer B 32 (50mmol NH) and about 50 parts of benzene. About 50 parts by volume of aunimolar solution of prepolymer A 22 (50 mmol NCO) are stirred into thisdispersion which is then stirred for a further 5 seconds, and thedispersion, which becomes viscous, is applied to glass plates 680 cm. inarea. After completion of polyaddition and evaporation of the solvent atabout 75 C. in a circulating air cupboard, a microporous film isobtained which has a permeability to water vapor of 8.6 mg./h./cm.

Example 49 About 100 parts by volume of water are dispersed in about 50parts by volume of a 0.5 molar solution in benzene of prepolymer B 32(25 mmol NH). About 50 parts by volume of a molar solution of anisomeric mixture of 80 percent 2,4- and 20 percent, 2,6-toluylenediisocyanate in ethyl acetate are added. The reaction mixture is stirredfor about 10 seconds and then applied to glass plates 680 cm. in area.After completion of the polyaddition and evaporation of the solvents atabout 75 C., in a circulating air cupboard, a microporous film isobtained which has a penneability to water vapor of4.9 mg./h./cm.

Example 50 About 20 parts of a 2-molar aqueous solution of hydrazine (40mmol NH;) and about parts by volume of water are dispersed in about 30parts of di-n-propyl ether and about 50 parts by volume of a 0.5 molarsolution of prepolymer B 33 (25 mmol NH). After the addition of about6.3 parts of a mixture of about 4 parts of 2,4-and about one part of2,6- toluylene diisocyanate (70 mmol NCO) in about 10 parts ofdi-n-propyl ether, the reaction mixture is stirred for a further 8seconds and then applied to glass plates 700 cm. in area. Polyadditionis completed at about 60 C. and the solvents are evaporated. Theresulting microporous film has a permeability to water vapor of 0.5mg./h./cm.

Example 51 About 80 parts by volume of water are dispersed in a mixtureof about 50 parts by volume of a 30 percent solution in benzene of aproduct prepared according to B 34 and about 30 parts of a 20 percentsolution in methylene chloride of a polycarbonate of4,4'-dihydroxy-diphenyl-2,2-propane, about 15 parts by volume of a molarsolution (15 mmol NCO) in ethyl acetate of a product according to A 22are added. After stirring for about 15 seconds the reaction mixture ispoured on to a commercial removable backing paper (for polyurethanes)1,000 cm. in area, polyaddition is completed in a circulating aircupboard at 75 C., and the solvents are evaporated.

The resulting microporous film has a permeability to water vapor of 1.4mg./h./cm.

Although the invention has been described in considerable detail in theforegoing for the purpose of illustration, it is to be understood thatsuch detail is solely for this purpose and that variations can be madeby those skilled in the art without departing from the spirit and scopeof the invention except as is set forth in the claims.

What is claimed is:

l. A process for making a microporous sheet structure which is permeableto water vapor which comprises dispersing into an organic polyaminehaving a molecular weight of from about 350 to about 6,000, water or anorganic nonsolvent to form a dispersion of water or organic nonsolventin the polyamine, mixing a substantially equivalent amount of an organicpolyisocyanate with the resulting dispersion, applying the resultingdispersion of reacting organic polyisocyanate and polyamine to asubstrate, completing reaction of the organic polyisocyanate with thepolyamine while evaporating the water or nonsolvent therefrom, saidnonsolvent being a nonsolvent for both the polyamine and thereactionproduct.

2. The process of claim 1 wherein the organic polyisocyanate isdissolved in an organic solvent therefor prior to mixing.

3. The process of claim 1 wherein the organic polyisocyanate is selectedfrom the group consisting of monomeric organic polyisocyanates, NCOterminated prepolymers prepared by reacting an excess of a monomericpolyisocyanate with an organic compound having active hydrogen atomsthat are reactive with NCO groups and mixtures thereof.

4. The process of claim 1 wherein the organic polyamine having amolecular weight of from about 350 to about 6,000 and at least two aminogroups is mixed with lower molecular weight polyamines, the quantity ofwhich does not exceed 50 mols percent based on the high molecular weightpolyamines.

5. The process of claim 1 wherein both the organic polyisocyanate andthe polyamine aredissolved or dispersed in organic solvents therefor.

6. The process of claim 1 wherein the organic polyamine having amolecular weight of from about 350 to about 6,000 and at least two aminogroups is a reaction product of an excess of a low molecular polyamineor hydrazine with an isocyanato terminated prepolymer.

7. The process of claim 1 wherein the polyamine is dissolved ordispersed in an organic solvent therefor prior to mixing.

8. The process of claim 1 wherein (b) is dispersed in the nonsolventbefore it is mixed with (a).

9. The process of claim 1 wherein water is dispersed into the organicpolyamine.

10. A microporous sheet structure prepared by the process of claim 1.

11. The process of claim 1 wherein a nonsolvent for the polyamine isdispersed into the polyamine.

12. The process of claim 11 wherein the polyamine is dissolved in asolvent which is evaporated with the nonsolvent when the reaction issubstantially complete.

13. The process of claim 12 wherein the vaporization number of thenonsolvent is at least 1% times that of the solvent.

2. The process of claim 1 wherein the organic polyisocyanate isdissolved in an organic solvent therefor prior to mixing.
 3. The processof claim 1 wherein the organic polyisocyanate is seleCted from the groupconsisting of monomeric organic polyisocyanates, NCO terminatedprepolymers prepared by reacting an excess of a monomeric polyisocyanatewith an organic compound having active hydrogen atoms that are reactivewith NCO groups and mixtures thereof.
 4. The process of claim 1 whereinthe organic polyamine having a molecular weight of from about 350 toabout 6,000 and at least two amino groups is mixed with lower molecularweight polyamines, the quantity of which does not exceed 50 mols percentbased on the high molecular weight polyamines.
 5. The process of claim 1wherein both the organic polyisocyanate and the polyamine are dissolvedor dispersed in organic solvents therefor.
 6. The process of claim 1wherein the organic polyamine having a molecular weight of from about350 to about 6,000 and at least two amino groups is a reaction productof an excess of a low molecular polyamine or hydrazine with anisocyanato terminated prepolymer.
 7. The process of claim 1 wherein thepolyamine is dissolved or dispersed in an organic solvent therefor priorto mixing.
 8. The process of claim 1 wherein (b) is dispersed in thenonsolvent before it is mixed with (a).
 9. The process of claim 1wherein water is dispersed into the organic polyamine.
 10. A microporoussheet structure prepared by the process of claim
 1. 11. The process ofclaim 1 wherein a nonsolvent for the polyamine is dispersed into thepolyamine.
 12. The process of claim 11 wherein the polyamine isdissolved in a solvent which is evaporated with the nonsolvent when thereaction is substantially complete.
 13. The process of claim 12 whereinthe vaporization number of the nonsolvent is at least 1 1/2 times thatof the solvent.